langchain/templates/anthropic-iterative-search/anthropic_iterative_search/retriever_agent.py

from langchain.agents import AgentExecutor
from langchain.chat_models import ChatAnthropic
from langchain.prompts import ChatPromptTemplate
from langchain.schema.output_parser import StrOutputParser
from langchain.schema.runnable import RunnableMap, RunnablePassthrough

from .agent_scratchpad import format_agent_scratchpad
from .output_parser import parse_output
from .prompts import retrieval_prompt
from .retriever import retriever_description, search

prompt = ChatPromptTemplate.from_messages([
    ("user", retrieval_prompt),
    ("ai", "{agent_scratchpad}"),
])
prompt = prompt.partial(retriever_description=retriever_description)

model = ChatAnthropic(model="claude-2", temperature=0, max_tokens_to_sample=1000)

chain = RunnablePassthrough.assign(
    agent_scratchpad=lambda x: format_agent_scratchpad(x['intermediate_steps'])
) | prompt | model.bind( stop_sequences=['</search_query>']) | StrOutputParser()

agent_chain = RunnableMap({
    "partial_completion": chain,
    "intermediate_steps": lambda x: x['intermediate_steps']
}) | parse_output

executor = AgentExecutor(agent=agent_chain, tools = [search], verbose=True)